Business, science and entertainment applications depend upon computers to process and record data, often with large volumes of the data being stored or transferred to nonvolatile storage media, such as magnetic discs, magnetic tape cartridges, optical disk cartridges, floppy diskettes, or floptical diskettes. Typically, magnetic tape is the most economical and convenient means of storing or archiving the data. Storage technology is continually pushed to increase storage capacity and storage reliability. Improvement in data storage densities in magnetic storage media, for example, has resulted from improved medium materials, improved magnetic read/write heads, improved error correction techniques and decreased areal bit sizes. The data capacity of half-inch magnetic tape, for example, is now measured in hundreds of gigabytes on 512 or more data tracks.
Occasionally in tape drives, error rates degrade as a result of accumulation of debris on the head. This debris can generally be removed by brushing or otherwise cleaning the head. However, drive space constraints hamper in situ head cleaning in a manner that does not jeopardize damaging the tape.
Another problem that is sometimes observed is suction. When the tape drive is in idle mode with the tape remaining in contact with the head, stiction between head and tape can develop. This can lead to a loss of tension or the tape sticking to the head. Combating stiction by roughening the head surface leads to spacing loss and tape wear. Preventing stiction by continuously moving the head with respect to the stationary tape can damage the tape and prematurely wear the head and actuator.